The mechanisms involved in the regulation of production and release of alveolar macrophage lysosomal enzymes are important to inhalation toxicology because of their participation in the digestion of endocytosed foreign materials and their role in the induction of lung damage during their release. The induction of lysosomal enzymes by morpholine in alveolar macrophages was examined. Morpholine and several related chemicals stimulated the synthesis of Alpha-mannosidase in alveolar macrophages.